Electrical circuits, such as logic and memory circuits, typically have output voltage values which convey information regarding the functionality and results of the particular circuit. For digital circuits, a high voltage level might indicate a logical ONE value, whereas a low voltage level might indicate a logical ZERO value. Maintaining and changing these output voltage levels results in power dissipation, as is commonly known in the art.
Particularly in the digital electronic art, many types of circuits operate synchronously, where several outputs can switch or otherwise change values at the same time. This synchronous operation generally results from a common clock or other control signal being used to initiate or trigger the change in output. For such a system, the amount of power required to support instantaneous switching can be significant.
The simultaneous switching of large numbers of circuit outputs also generates a substantial amount of heat, which must be removed or dissipated. This adds to the overall cost of the system, by either requiring some type of heat sink or by not providing other functions that might otherwise be included within the same electrical/electronic device packaging.
In addition, such simultaneous switching increases the amount of ground bounce which may potentially occur in the system. Although ideally the ground voltage remains at zero volts, certain transient voltage spikes can appear on the ground signal when switching large voltages or currents to ground. These transient voltage spikes, also known as ground bounce, can cause operational errors in, and/or physical damage to, the electrical/electronic devices.